1. Technical Field
This invention generally relates to the excavation and construction field, and more specifically relates to devices for covering holes.
2. Background Art
Various projects often require digging a hole in the ground. For example, installing power poles requires digging or drilling a hole, then placing the power pole into the hole. Some construction projects use post and pier construction, which also requires drilling holes for concrete posts. Often a trench needs to be excavated in which water or power lines need to be run. One common problem with many types of excavations and other types of holes relates to the danger in leaving the hole uncovered. A person or animal could inadvertently step into an uncovered hole, possibly causing injury (such as a broken leg) if the hole is small, or causing the person or animal to fall into a larger hole, possibly causing serious injury or even death.
To reduce the danger of an open hole, sometimes a flat piece of metal or plywood is placed over the hole to stop a person or animal from stepping or falling into the hole. This solution works relatively well for protecting people who know the hole is there and do not wish to disturb the hole. However, simply covering the hole with metal or plywood does not work well for keeping curious children or vandals out of the hole. A child or vandal could easily slide a piece of metal or plywood out of the way, making the hole accessible. The child could then be injured by falling or playing in the hole. A vandal could fill the hole with rocks, dirt, glass, or other material, making removal of these materials necessary before the hole may be used for its intended purpose. In addition, a piece of metal or plywood could be accidentally shifted to not completely cover the hole by an animal (such as a cow) walking on the metal or plywood.
Leaving a hole uncovered could lead an individual or company to be exposed to significant financial liability for injuries caused by the hole. Simply covering the hole with a sheet of material is not sufficiently safe or secure to keep children and vandals out of the hole. Without a device for securely covering a hole, the construction and excavation industries will continue to suffer from inadequate methods and devices for covering an open hole, potentially exposing companies in these industries to significant financial liability from injuries and damages caused by unsecured or uncovered holes.
According to the preferred embodiments, a hole cover device is used to cover all or a portion of an excavation or hole. The hole cover device includes a top plate through which extends a screw mechanism that is coupled to a plurality of movable arms below the top plate. When a hole needs to be covered, the lower portion of the hole cover device (including the movable arms) is placed in the hole, with the top plate resting on the ground around the hole. The screw mechanism that extends above the top plate is then turned, which causes the movable arms below the top plate to extend outwardly until they engage the sides of the hole, making removal of the hole cover device very difficult. The screw mechanism may then be secured using a lock to assure the hole cover device may only be removed by authorized personnel. In a preferred embodiment, the hole cover device is for a circular hole, such as those drilled for fenceposts and electrical power poles, and therefore has a circular top plate with a diameter larger than the hole to be drilled. The screw mechanism is coupled to three lower arms that are preferably 120 degrees apart and that extend radially from the screw mechanism. When the hole cover device is placed in a hole and the screw mechanism is engaged, the movable arms deploy to an extended position. Because the three movable arms are equally spaced around the circle, extending the movable arms results in the hole cover device being automatically centered in the hole. Once the movable arms securely engage the sides of the hole, the screw mechanism may be locked to prevent unauthorized people from removing the hole cover device.
The foregoing and other features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.